The history of the discovery of Pluto
THE SEARCH FOR AND DISCOVERY OF THE NINTH PLANET
Borislav Of Slavoljub
13 March 1783, William Herschel discovered the planet Uranus. This immediately increased the size of the Solar System twice. According to the observations of the planet was determined by its orbit and the theory of the motion of Uranus. However, the observed motion of Uranus differed systematically from the predicted. This discrepancy has allowed John Adams and Urbain the Verrier theoretically predict the existence of the eighth planet – Neptune. open by Johann Galle on 23 September 1846. The discovery of Neptune was a triumph for the theory of universal gravitation of Newton.
Taking into account the influence of Neptune on Uranus was possible to reduce the discrepancies between the theoretical and the observed motion of Uranus dozens of times, but full precision was not achieved. In 1848 the American astronomer B. pierce suggested the existence of a ninth planet. In 1874 S. great effect constructed a new theory of the motion of Uranus, taking into account perturbations from Jupiter, Saturn and Neptune. It also presupposes the existence of a transneptunian planet.
The search for the unknown planet began in the late 19th century, astronomer Percival Lovell (1855-1916). In 1896 he clarified the errors in the motion of Uranus. And, based on its calculations, has suggested that the ninth planet has a period of revolution in years and 282 lustre 12-13 magnitudes. In 1905 Lovell started practical search, taking pictures of the sky on the 5-inch telescope. For this alone he Photographed the same patch of sky with a period of several days, and compared the resulting images overlaid on each other. Finding nothing, Lovell in 1908 began studying the motion of Neptune. One of the most likely constellation to find “planet X” he considered the constellation Gemini. Looking at last years took their toll on the health of the astronomer, he died in 1916.
Ironically, after 15 years in the photographs of Lovell received in 1914-1915, “planet X” was found. The astronomer, looking for the object with glitter 12-13 magnitude, simply did not pay attention to the star of 15 magnitude.
In 1919 colleague Lowell of Harvard Observatory, Henry Pickering repeated the calculation of Lovell, using data of the trajectories of two planets – Uranus and Neptune. He also pointed to the constellation Gemini as a place where to find the ninth planet. At the request of the astronomer Pickering Milton Humason from the Observatory mount Wilson began Photographing the constellation. Humason really photographed “planet X” on two of his LPS, but he was unlucky, and he didn’t notice it. On one planet image was spoiled by a defect on the disc, and on the other the image of a bright nearby star closed it. Some time later, Humason gave up the search.
After that, the interest of astronomers in the search for a ninth planet began to fall. Only at the Observatory Lowell had planned further exploration. In the late 20-ies of brother Lowell, Abbot Lawrence made additional cash contributions to Fund the Observatory. Part of that money went to a new wide-angle 32,5 cm telescope, is able in one hour to photograph the stars up to 17th magnitude star on the area of 160 square degrees, i.e. 1/260 part of the entire visible sky. New camera started to work on 1 April 1929.